The present invention relates generally to microelectromechanical systems (MEMS) structures and fabrication techniques and, more particularly, to microelectromechanical switches for integrated circuits and methods of fabricating microelectromechanical switches.
Components fabricated with the emerging technologies of microelectromechanical systems (MEMS) are being incorporated in an increasing number of consumer applications including, but not limited to, automotive electronics, medical equipment, cell phones, hard disk drives, computer peripherals, and wireless devices. MEMS technology is directed at forming miniaturized electro-mechanical devices and structures using micro-fabrication techniques. MEMS devices are characterized by some form of mechanical functionality, which is typically in the form of a least one moving structure. Structures may be formed on a suitable substrate by a series of processing steps involving thin film depositions that are photolithographically masked and etched. MEMS mechanical elements, sensors, and actuators may be integrated on a common substrate with complementary metal-oxide-semiconductor (CMOS) devices.
One type of MEMS based microelectronic device that has wide applicability to the electronics industry is the MEMS switch. MEMS switches rely on mechanical movement of a deflection electrode to make or break contact with a stationary electrode, thus forming a short circuit or an open circuit depending on the position of the deflection electrode. MEMS switches are typically actuated by using electrostatic forces to produce the mechanical movement required to change the state of the switch. MEMS switches are noted for their low power consumption, high isolation in the off state, low insertion loss in the on state, and high linearity, typically outperforming switches relying on semiconductor devices such as field-effect transistors (FETs). Switches provide an important building block in many electronic systems, and the performance characteristics of MEMS switches make them particularly attractive for providing signal switching functions in mixed signal, communications, and radio frequency integrated circuit applications.
Accordingly, there is a need for improved MEMS design structures and methods of fabricating those structures that provide for integration of MEMS switches with conventional integrated circuits.